1. Field of the Invention
The present invention is concerned with a mechanical restraint to resist the influence of torque applied to fittings, particularly fittings of vessels such as fluid containment tanks. More particularly, it is directed to a fitting including a restraint and a restraint which can be mounted to a fitting and positioned interiorly of a fluid tank in order to avoid damage to the sealing integrity between the outlet assembly and the tank.
2. Description of the Prior Art
Vessels for holding liquids are used in a variety of industries and while they may be configured differently and constructed of various materials. A variety of different fittings for various purposes such as inlet, instrumentation and the like are provided on a tank. Fittings which are used as part of a discharge outlet may be of particular interest as they are often constructed to use gravity so as to discharge the liquid contents of the tank through a discharge outlet which often extends through a side wall of the tank and is located near the bottom wall of the tank. This arrangement is advantageous in that gravity supplies the necessary force to drain the liquid from the tank, and that various valves, hoses, pipes or other attachments can be coupled to the outlet fitting. Examples of just a few of the many types of tanks employing this concept may be seen, for example, in U.S. Pat. Nos. 6,079,580, 6,318,581, 6,474,496 and 6,484,899, the disclosures of which are incorporated herein by reference.
In tanks molded of synthetic resin, the fittings, such as outlet fittings, may either be coupled to an integrally molded outlet pipe or tubulation such as is shown in U.S. Pat. No. 6,079,580 or may be inserted into an opening in the sidewall of the tank as is shown in U.S. Pat. Nos. 6,474,496 and 6,484,899. To these fittings, further pipes, valves, hoses or other devices are often attached, as is shown for example in U.S. Pat. No. 7,195,284, the entire disclosure of which is incorporated herein by reference. These attachments to the fitting can become especially heavy, especially when filled with liquid. This in turn imparts a significant torque arm onto the sidewall of the tank. One partial answer to dealing with this stress is to provide additional support exteriorly of the tank for the extended pipe, as is shown in U.S. Pat. No. 7,195,284. However, such measures are often overlooked or removed, resulting in a cantilever support from the outlet fitting. Moreover, even when such support is provided, the length of a pipe and its fluid contents in a long length of pipe may still impart a significant stress on the portion of the tank adjacent the outlet. This stress can cause deformation, such as warping of the tank wall which results in leaks, or even worse, stress fractures which can destroy the usefulness of the tank.
Thus, there has developed a need for some device which can easily and economically counteract the torque which is applied to various types of fittings used on tanks and other vessels, and in particular outlet fittings.